Suppose you have a function requiring a count argument, and you would like to be able to invoke it with a mapping, and also allow the count to be prefixed to the mapping, like you can with for example {count}CTRL-^ (to edit the [count]th file in the buffer list).

Here is an example of code that can be used to call a Foo() function with such a prefix count argument. All it shows is the structure required for such a thing to work (well, it's the best the author of the tip was able to come up with). Given the following, typing 42,a will echo FOO: 42: